Tested with P/S and S/B Chitterspine Skitterling. I'm using one in my Stratholme Challenge Walkthrough so I have to use a different one here. Due to Snail Mail's charge round, Skitterlings were always capable of debuffing the Mailemental with Black Claw + Shattered Defenses.
Be sure to use a fully healed Rabbit while doing this in the Challenge, sometimes it needs to Stampede and not only watch Soul Collector die ;-)
At least one of the pets for this strategy require the use of a specific breed.
The strategy offers a TD script that can be used with the TD Script addon. You can copy the script by clicking on the button to the left of the pets.